The present invention relates generally to valve devices and more specifically to a reducing valve assembly for steam and compressed air or gases, especially to a construction of a reducing valve which is equipped with a vapor-liquid separator.
In boilers or compressors, steam or gas under pressure is reduced to a desired pressure by means of a reducing valve before reaching the equipment which utilizes the steam or the compressed air. Steam or air usually contains condensed water and solid matter. Since water particles and foreign matter can cause wear or corrosion in the valve mechanisms, for example, in the valve seat or other sliding components thereof, reducing valve mechanisms will often malfunction and pressure may build up in the downstream system due to leakage of steam or air eventually exceeding the preset value. Such water particles and foreign matter which have passed the reducing valve may also cause damage or decreased efficiency of the equipment utilizing the steam or air.
In prior art technology, in order to eliminate condensate and foreign matter, a vapor-liquid separator and a strainer have been fitted upstream of the reducing valve in sequence. Each provides flanges to be fitted to the piping of the assembly and the vapor-liquid separator is so constructed that water particles and foreign matter are separated by causing steam or air to impinge on a barrier provided in the separating chamber. A drain valve and a strainer therefor are fitted to the separator. The strainer is placed between the separator and the reducing valve and is fitted with a blow-down valve.
Prior art mechanisms of this type described result in the requirement for long piping and large installation space. Additionally, since the vapor-liquid separator may display a poor separating characteristic, a finer and consequently larger strainer may be required to be installed downstream. Further additional valves and components may be required, thereby resulting in complex piping and higher installation costs.
Accordingly, the present invention is intended to provide a reducing valve assembly which includes a vapor-liquid separator wherein many of the prior art problems are overcome. In accordance with the present invention, a vapor-liquid separator may be incorporated in the reducing valve assembly and a strainer may, if required, also be incorporated because the need for a large filter is eliminated. The invention seeks to provide a reducing valve assembly which is only slightly larger in size than an ordinary reducing valve because of the provision of a sump.